Determine whether the statements below are true or false. If a statement is false, provide the correct information or revise the statement to make it correct.

The progeny of a trihybrid cross are expected to have one of 27 different genotypes.

Determine whether the statements below are true or false. If a statement is false, provide the correct information or revise the statement to make it correct.

If a dihybrid plant is self-fertilized,

(1) 9/16 of the progeny will have the same phenotype as the F₁ parent.

(2) 1/16 of the progeny will be true-breeding.

(3) 1/2 of the progeny will be heterozygous at one or both loci.

In the datura plant, purple flower color is controlled by a dominant allele, P. White flowers are found in plants homozygous for the recessive allele p. Suppose that a purple-flowered datura plant with an unknown genotype is self-fertilized and that its progeny are 28 purple-flowered plants and 10 white-flowered plants.

Use the results of the self-fertilization to determine the genotype of the original purple-flowered plant.

In the datura plant, purple flower color is controlled by a dominant allele, P. White flowers are found in plants homozygous for the recessive allele p. Suppose that a purple-flowered datura plant with an unknown genotype is self-fertilized and that its progeny are 28 purple-flowered plants and 10 white-flowered plants.

If one of the purple-flowered progeny plants is selected at random and self-fertilized, what is the probability it will breed true?

The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

    Cross 1:  P₁: Male leopard x male mottled

             F₁: All mottled

             F₂: 70 mottled, 22 leopard

    Cross 2:  P₁: Male mottled x female leopard

             F₁: All mottled

             F₂: 50 mottled, 18 leopard

Which of the phenotypes is dominant? Explain your answer.

The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

    Cross 1:  P₁: Male leopard x male mottled

             F₁: All mottled

             F₂: 70 mottled, 22 leopard

    Cross 2:  P₁: Male mottled x female leopard

             F₁: All mottled

             F₂: 50 mottled, 18 leopard

Compare and contrast the results of the reciprocal crosses in the context of autosomal gene inheritance.

The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

    Cross 1:  P₁: Male leopard x male mottled

             F₁: All mottled

             F₂: 70 mottled, 22 leopard

    Cross 2:  P₁: Male mottled x female leopard

             F₁: All mottled

             F₂: 50 mottled, 18 leopard

In the F₂ progeny from both crosses, what proportion is expected to be homozygous? What proportion is expected to be heterozygous?

The dorsal pigment pattern of frogs can be either 'leopard' (white pigment between dark spots) or 'mottled' (pigment between spots appears mottled). The trait is controlled by an autosomal gene. Males and females are selected from pure-breeding populations, and a pair of reciprocal crosses is performed. The cross results are shown below.

    Cross 1:  P₁: Male leopard x male mottled

             F₁: All mottled

             F₂: 70 mottled, 22 leopard

    Cross 2:  P₁: Male mottled x female leopard

             F₁: All mottled

             F₂: 50 mottled, 18 leopard

Propose two different genetic crosses that would allow you to determine the genotype of one mottled frog from the F₂ generation.

Black skin color is dominant to pink skin color in pigs. Two heterozygous black pigs are crossed.

What is the probability that their offspring will have pink skin?

Black skin color is dominant to pink skin color in pigs. Two heterozygous black pigs are crossed.

What is the probability that the first and second offspring will have black skin?

Black skin color is dominant to pink skin color in pigs. Two heterozygous black pigs are crossed.

If these pigs produce a total of three piglets, what is the probability that two will be pink and one will be black?

A male mouse with brown fur color is mated to two different female mice with black fur. Black female 1 produces a litter of 9 black and 7 brown pups. Black female 2 produces 14 black pups.

What is the mode of inheritance of black and brown fur color in mice?

A male mouse with brown fur color is mated to two different female mice with black fur. Black female 1 produces a litter of 9 black and 7 brown pups. Black female 2 produces 14 black pups.

Choose symbols for each allele, and identify the genotypes of the brown male and the two black females.

The following figure shows the results of Mendel's test-cross analysis of independent assortment. In this experiment, he first crossed pure-breeding round, yellow plants to pure-breeding wrinkled, green plants. The round yellow are crossed to pure-breeding wrinkled, green plants. Use chi-square analysis to show that Mendel's results do not differ significantly from those expected.

An experienced goldfish breeder receives two unusual male goldfish. One is black rather than gold, and the other has a single tail fin rather than a split tail fin. The breeder crosses the black male with a female that is gold. All the F₁ are gold. She also crosses the single-finned male to a female with a split tail fin. All the F₁ have a split tail fin. She then crosses the black male to F₁ gold females and, separately, crosses the single-finned male to F₁ split-finned females. The results of the crosses are shown below.

  Black male x F₁ gold female:

    Gold        32

    Black       34

  Single-finned male x F₁ split-finned female:

    Split fin       41

    Single fin    39

What do the results of these crosses suggest about the inheritance of color and tail fin shape in goldfish?

An experienced goldfish breeder receives two unusual male goldfish. One is black rather than gold, and the other has a single tail fin rather than a split tail fin. The breeder crosses the black male to a female that is gold. All the F₁ are gold. She also crosses the single-finned male to a female with a split tail fin. All the F₁ have a split tail fin. She then crosses the black male to F₁ gold females and, separately, crosses the single-finned male to F₁ split-finned females. The results of the crosses are shown below.

Is black color dominant or recessive? Explain. Is single tail dominant or recessive? Explain.

An experienced goldfish breeder receives two unusual male goldfish. One is black rather than gold, and the other has a single tail fin rather than a split tail fin. The breeder crosses the black male to a female that is gold. All the F₁ are gold. She also crosses the single-finned male to a female with a split tail fin. All the F₁ have a split tail fin. She then crosses the black male to F₁ gold females and, separately, crosses the single-finned male to F₁ split-finned females. The results of the crosses are shown below.

  Black male x F₁ gold female:

    Gold         32

    Black        34

  Single-finned male x F₁ split-finned female:

    Split fin        41

    Single fin     39

Use chi-square analysis to test your hereditary hypothesis for each trait.

The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.

What is the most likely mode of transmission of albinism in this family? 

The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.

Using allelic symbols of your choice, identify the genotypes of the male and his two mates in generation I. 

The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.

The female I-1 and her mate, male I-2, had four children, one of whom has albinism. What is the probability that they could have had a total of four children with any other outcome except one child with albinism and three with normal pigmentation? 

The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.

What is the probability that female I-3 is a heterozygous carrier of the allele for albinism? 

The accompanying pedigree shows the transmission of albinism (absence of skin pigment) in a human family.

One child of female I-3 has albinism. What is the probability that any of the other four children are carriers of the allele for albinism? 

A geneticist crosses a pure-breeding strain of peas producing yellow, wrinkled seeds with one that is pure-breeding for green, round seeds.

Use a Punnett square to predict the F₂ progeny that would be expected if the F₁ are allowed to self-fertilize.

A geneticist crosses a pure-breeding strain of peas producing yellow, wrinkled seeds with one that is pure-breeding for green, round seeds.

What proportion of the F₂ progeny are expected to have yellow seeds? Wrinkled seeds? Green seeds? Round seeds?

A geneticist crosses a pure-breeding strain of peas producing yellow, wrinkled seeds with one that is pure-breeding for green, round seeds.

What is the expected phenotype distribution among the F₂ progeny?

Suppose an F₁ dihybrid (round yellow plant from Problem 16) is crossed to the pure-breeding green, round parental strain. Use a forked-line diagram to predict the phenotypic distribution of the resulting progeny.

In pea plants, the appearance of flowers along the main stem is a dominant phenotype called 'axial' and is controlled by an allele T. The recessive phenotype, produced by an allele t, has flowers only at the end of the stem and is called 'terminal.' Pod form displays a dominant phenotype, 'inflated,' controlled by an allele C, and a recessive 'constricted' form, produced by the c allele. A cross is made between a pure-breeding axial, constricted plant and a plant that is pure-breeding terminal, inflated.

The F₁ progeny of this cross are allowed to self-fertilize. What is the expected phenotypic distribution among the F₂ progeny?

In pea plants, the appearance of flowers along the main stem is a dominant phenotype called 'axial' and is controlled by an allele T. The recessive phenotype, produced by an allele t, has flowers only at the end of the stem and is called 'terminal.' Pod form displays a dominant phenotype, 'inflated,' controlled by an allele C, and a recessive 'constricted' form, produced by the c allele. A cross is made between a pure-breeding axial, constricted plant and a plant that is pure-breeding terminal, inflated.

Suppose that all of the F₂ progeny with terminal flowers, i.e., plants with terminal flowers and inflated pods and plants with terminal flowers and constricted pods, are saved and allowed to self-fertilize to produce a partial F₃ generation. What is the expected phenotypic distribution among these F₃ plants?

In pea plants, the appearance of flowers along the main stem is a dominant phenotype called 'axial' and is controlled by an allele T. The recessive phenotype, produced by an allele t, has flowers only at the end of the stem and is called 'terminal.' Pod form displays a dominant phenotype, 'inflated,' controlled by an allele C, and a recessive 'constricted' form, produced by the c allele. A cross is made between a pure-breeding axial, constricted plant and a plant that is pure-breeding terminal, inflated.

If an F₁ plant from the initial cross described above is crossed with a plant that is terminal, constricted, what is the expected distribution among the resulting progeny?

In pea plants, the appearance of flowers along the main stem is a dominant phenotype called 'axial' and is controlled by an allele T. The recessive phenotype, produced by an allele t, has flowers only at the end of the stem and is called 'terminal.' Pod form displays a dominant phenotype, 'inflated,' controlled by an allele C, and a recessive 'constricted' form, produced by the c allele. A cross is made between a pure-breeding axial, constricted plant and a plant that is pure-breeding terminal, inflated.

If the plants with terminal flowers produced by the cross in part (c) are saved and allowed to self-fertilize, what is the expected phenotypic distribution among the progeny?